TP 953 
. V5 

COAL TAR 
INTERMEDIATE 
PLANTS 



cz-NAPHTHYLAMINE 


WRITTEN FOR UNDERWRITING PURPOSES 
BY 

WM. VLACHOS 

FIRE INSURANCE INSPECTOR 
204 WALNUT PLACE 

PHILADELPHIA 


















BUSINESS, THE PLAGUE AND PLEASURE OF MY LIFE, 
THOU CHARMING MISTRESS, THOU VEXATIOUS WIFE;” 

—BEN FRANKLIN 


Poor Richard, 
1742. 



COAL TAR 
INTERMEDIATE 
PLANTS 

BY 

WILLIAM VLACHOS 


J 

) > 
) > 

) ) ) 

A 


I 


Copyright 1918 

BY 

William Vlachos 








J 


“Crafty men contemn studies, simple men admire them, and wise men 


use them; ” 


—LORD FRANCIS BACON, 


“ Essays ” 


NOV 27 1318 


©CU506724 


-Vvo \ 



ACCOMPLISH 

THE 

IMPOSSIBLE 

The “Great War” has been a hard taskmaster. 
It has forced us, Nationally and individually, 
to accomplish things formerly thought impossible. 

COAL 

TAR 

INDUSTRY 

The creation of our OWN Coal Tar Industry 
(for we had to have TNT) has been our most 
difficult and therefore our most creditable indus¬ 
trial achievement. Added to our magnificent 
Steel Industry, it made us invincible in War, and 
during Peace times it will emancipate our indus¬ 
trial and scientific life from all foreign control. 

TARIFF 

Let us hope that during the Reconstruction 
Period this priceless National asset will be thor¬ 
oughly appreciated and will be properly safe¬ 
guarded by suitable tariff legislation. 

SAFETY 

AND 

PROTECTION 

We fire insurance men will, of course, gladly 
do our share to help this vital industry, still in 
its chrysalis state, expand into a vigorous entity. 
This youngest industry needs our careful guidance 
along the to us familiar paths of “safety” and 
“protection”, as it involves the most powerful 
and most complicated chemical processes. 

FASCINATING 

Therefore let us patiently continue our study 
of the Coal Tar Plants, always bearing in mind 
that we are not chemists, but just plain business 
men engaged in the “fascinating” pursuit of 
fire underwriting. 

5 


NOT ESPECIALLY 
REMUNERATIVE 

FIRST PAMPHLET 

BENZOL 

NAPHTHALENE 

ANTHRACENE 

CRUDES 


I use the word “fascinating” purposely, for 
what can be more interesting (even if it is not 
especially remunerative) than our work, which 
brings us in the closest relation with all and every 
kind of manufacture and all manner of men, even 
men without manners. 

In the “first” pamphlet, entitled “Coal Tar 
Distilling Plants”, we commenced with the basic 
material of the entire industry, Coal Tar, and 
placing it in a fire heated still we split it up into: 
Light Oil, Middle Oil, Heavy Oil, Anthracene Oil 
and Pitch. 

We placed the Light Oil in steam heated stills 
and fractioned off: Benzol, Toluol, Xylol and 
Solvent Naphtha. 

From the Middle Oil we obtained Naphthalene, 
Phenol and Cresol. 

Finally we extracted Anthracene from the 
anthracene oil, and, if my memory serves me 
rightly, we did this in fifteen short lines of print¬ 
ing, which is, let us hope, a record. 

In other words, we obtained the “crudes”, and 
the “first” pamphlet should have ended “right 
there”. However in the midst of the war, 
patriotism makes unusual demands, so we went 
right on and made phenol synthetically, because 
the ammunition makers needed it so badly, and 
having carried out our patriotic impulses we 
added for good measure the manufacture of the 
two most widely used Intermediates: Mono- 
Nitro-Benzol and Aniline Oil. 


6 


DYE 

INTERMEDIATES 


THIRD 

PAMPHLET 


CHRONIC 

CHEMISTRY 


EXPLOSIVE 

INTERMEDIATES 


INTERLINKED 


UNLIMITED 

NUMBER 


EIGHT 

PROCESSES 


Let us now, in this “second” pamphlet, make a 
study of the balance of the dye Intermediates, 
thus completing the last step on the rocky road 
to the Aniline, or, more properly speaking, the 
Synthetic Dyes. 

We shall reserve the Dyes for a “third” pamph¬ 
let in which we shall be able to feast ourselves on 
the explosiveness of the diazo salts and the 
intricacies of Synthetic Indigo. 

After that I promise not to annoy you again 
with Organic Chemistry or, as one stenographer 
wrote: “chronic” chemistry. 

It must be emphasized that several of the 
Intermediates, such as Aniline Oil, Dinitro- 
phenol, Monochlorbenzol, Dimethylaniline, Di- 
phenylamine, etc., are not only “Dye” Inter¬ 
mediates but are also used as intermediates in 
the “Explosive” industry. 

In other words the manufacture of Coal Tar 
Dyes and the manufacture of military explosives 
are thoroughly interlinked, and the best way to 
insure our National safety is to foster the Coal 
Tar Industry in ALL its branches. 

There are, technically speaking, about 290 
Intermediates. It would require quite a volume 
to discuss each one separately, but their manu¬ 
facture calls, roughly speaking, for eight principal 
processes: 

(1) Sulphonation 

(2) Nitration 

(3) Halogenation 

(4) Reduction 


7 


OTHER 

PROCESSES 

(5) Alkali Fusion 

(6) Alkylation 

(7) Amidation 

(8) Acylation 

There are other processes, such as nitrosation, 
oxidation, hydrolysis, condensation, etc., but as 
eight processes will sorely try your patience, we 
will let that suffice. 

SULPHONATION 

The “first” process we shall discuss is “Sulphon- 
ation”, a common process in the Intermediate 
Manufacturing Plants. As its name indicates, 


SULPHURIC ACID it depends on the action of sulphuric acid, of 


SULPHONATING 

KETTLE 

various strengths, on benzol, toluol, aniline oil, 
naphthalene or what not. 

The sulphuric acid is first placed in a sulphon¬ 
ating kettle, which is generally a round bottomed, 
cast-iron vessel, preferably lead-lined, equipped 
with more or less complex, power-driven stirring 
apparatus. 


WITHOUT STIRRING In some of the latest plants, sulphonating of 


APPARATUS 

benzol is now done without stirring apparatus. 

TEMPERATURE 

CONTROL 

The temperature of the sulphonation, which 
varies decidedly in different processes, is con¬ 
trolled by running brine, cold water or steam 
through the outer jacket of the kettle, and in 
some processes even a hot oil bath has to be 
employed. 

SYNTHETIC 

PHENOL 

On pages 15 and 16 of the “first” pamphlet you 
will find a short description of the sulphonating 
of benzol as carried out in the manufacture of 
synthetic phenol, and there you will also find a 
paragraph on the hazard involved. 


8 


DANGEROUS 

PROCESS 


MONO 

Dl 

TRI 


NITRATION 


MIXED ACID 


NITRATING PANS 


STIRRING 

APPARATUS 


As far as we insurance men are concerned, we 
are always safe in assuming that sulphonating 
is a dangerous process, both from a fire and 
explosion standpoint, and we should insist on the 
sulphonating kettles being located in a well cut 
off and, preferably, fire-proof section of the plant. 

In sulphonating, as in nitrating, the process 
may go only into the “mono” stage, or it may 
continue into the “di” stage or into the “tri” 
stage. The degree of hazard involved is, broadly 
speaking, as the numerical relation. 

Nitration, the “second” process on our list, is the 
bugbear of our business. Before the war, we had, 
very justly, a wholesome respect for “nitric 
acid”, but now we all know that nitric acid 
“plus” a coal tar product means a first class 
chance for a loss, either firewise or explosionwise. 

Nitrating of benzol, toluol, phenol, aniline oil, 
naphthalene, etc., is done with a mixture of nitric 
and sulphuric acids. The nitric acid does the 
work. The sulphuric acid simply absorbs the 
water evolved in the process. Some chemists 
believe, and with reason, that the sulphuric acid 
first sulphonates the material after which the 
nitric acid does the nitrating. 

The nitrating pans, which may have a capacity 
of one to several thousand gallons, are made of 
heavy cast-iron and are equipped with jackets for 
brine, water or steam, and often contain interior 
coils for cooling. 

The pans are equipped with power-stirring 
apparatus and, of course, are “air tight”. 


9 


EXPLOSIOMS 


SAFETY 

VALVES 


HIGH PRESSURE 
GAS 

12,000 TIMES 


The material to be nitrated, say benzol, is 
forced by compressed air into the nitrating pan, 
the agitator or stirrer is started, and, after it has 
attained a speed of 60 to 140 revolutions per 
minute (depending on the type of apparatus) the 
mixed nitric and sulphuric acid is slowly run into 
the nitrating kettle. 

If, through carelessness, the mixed acid is run 
in before the stirrers are in operation, an explosion 
is quite likely to occur, in fact, several disastrous 
explosions have occurred from this cause. 

When the rapidly revolving material is being 
mixed with the nitric and sulphuric acid, the 
temperature rises through the heat created by 
the chemical action. 

Strange to say, if the temperature should NOT 
rise, we again incur the danger of explosion. 

On pages 19 and 20 of the “ first” pamphlet you 
will find a short description of the nitrating of 
benzol. 

Now some one will rise to remark: “Why not 
install SAFETY VALVES? Safety valves have 
almost eliminated boiler explosions, why not put 
them on nitrating pans”. Fact is, they ARE put 
on nitrating pans as well as on sulphonating 
kettles and autoclaves, but they soon become 
inoperative through the action of the various 
acids, crystallization of the coal tar products, etc. 
Also they must, of necessity, be too small to carry 
off the enormous amount of high pressure gas 
that is generated when the liquid or solid materials 
that are being nitrated are instantaneously trans¬ 
formed into gases with a volume ten to twelve 
thousand times as great as that of the original 
substance. 


10 


You might just as well put a safety valve on a 
high explosive shell; it will explode just the same. 


CONTINUOUS 

NITRATING 

APPARATUS 


FIRE-PROOF 

NITRATING 

BUILDING 


POOR 

BEHAVIOR 

OF 

WIRE-GLASS 


CONCRETE 


HOMOGENEOUS 


NITRATE 
OF SODA 


You may, in your inspections, come across a 
“continuous” nitrating plant, but you will 
readily understand that any apparatus containing 
nitric acid in physical motion and in chemical 
action must, and does, rapidly deteriorate. Its 
upkeep, when in “continuous” operation, is 
almost impossible to maintain. For that reason 
“continuous” nitrating apparatus is likely to 
explode by becoming defective, and is, quite 
naturally, undesirable from our standpoint. 

Whether benzol, toluol, phenol, aniline oil or 
naphthalene is being nitrated, we are perfectly 
justified in insisting on it being done in a separate, 
fire-proof building, preferably with plenty of glass 
in the wall sections, so as to retard an explosion as 
little as possible. 

We fire insurance men have been educated to 
such a high regard for “wire-glass” that it will no 
doubt be quite a shock to you to learn that wire- 
glass is more easily destroyed by the force of an 
explosion than ordinary glass. This holds good 
in both horizontal and vertical positions, in other 
words whether in windows or in sky-lights. 

Similarly does “solid” concrete stand an 
explosion much better than “reinforced” con¬ 
crete, which breaks along the lines of the re¬ 
inforcement. 

The more “homogeneous” a body, the better 
it will withstand a blow. 

Nitration can also be carried on in certain pro¬ 
cesses with nitrate of soda and sulphuric acid. 


11 


FLAMELESS 

Of course, we can only insure the “mono” 
process. The “di” nitrating process is entirely 
too close to the “tri” nitrating process for com¬ 
fort. 

“Di” nitro compounds are sometimes referred 
to as “safety” or “flameless” explosives, but do 
not take that flamete business too seriously. 
As to the “safety” part, just ignore it. 

The other day I encountered a “di”-nitro- 
toluol still which had “blown up”, and strange 

STILL MOVED 

to say, no damage resulted, except that the 
entire apparatus had moved about six inches. 
But it would be quite rash to guarantee that this 
still will behave in as ladylike a manner the next 
time. 

TNB 

TNT 

TNP 

The “tri” nitrates of benzol, toluol and phenol 
are our most famous military explosives known as 
T N B, T N T and T N P. 

PICRIC ACID 

TNP, or tri-nitro-phenol, is the oldest and the 
most powerful of the “high” explosives. One 
pound of T N P will, theoretically, throw a ton 
of earth 300 feet into the air. It was discovered 
in 1771. 

TNP 

If Napoleon, who was bom in 1769, had 
only known how to utilize T N P, our Broad¬ 
way brethren would be conversing in French in¬ 
stead of Manhattanese. As it happens, the 
French army did not adopt TNP for filling 
shells till 1885, 114 years after its discovery. It 
has been given various fancy names such as: 
melinite, lyddite, pertite, shimosite, dunnite, but 
it all means the same thing. 

Picric acid is fairly stable and is insensitive to 
* ordinary shocks, but it has one nasty habit. 
With metals, such as lead and copper, it forms 


12 


PICRATES 

“picrates”, which are most sensitive to shock. 
You will therefore notice how carefully the in¬ 
teriors of the military shells are coated with 
shellac before picric acid is placed in them. 

TNT 

Picric acid is the MOST powerful of the high 
explosives. Still, the disaster at Morgan has 
given William Street an excellent demonstration 
that tri-nitro-toluol also has a right to be con¬ 
sidered rather forceful, even if its power is sec¬ 
ondary to picric acid. 

1902 

Tri-nitro-toluol was adopted by the German 
army in 1902 for filling shells, and it was not, as 
some writers would lead us to believe, a carefully 
kept secret sprung suddenly on an unsuspecting 
world. It was adopted because it is best for 
storage (very slow deterioration), because it does 
not form highly sensitive and explosive salts with 
metals, and because it is the safest to handle. 
Take for example: we have to heat picric acid to 
about 253° F. before it can be cast, but when 
using T N T we only need about 177° F. 

BELGIUM 

The first time the general public became im¬ 
pressed with the powers of T N T was in the 
Fall of 1914 when the Germans used it to blow 
the concrete Belgian forts to atoms. 

And, it is an undeniable fact that the bulk 

BY-PRODUCT 

of the raw material used was simply and purely 
a by-product of the synthetic dye plants. Let 
us make sure therefore that we continue to 
manufacture our OWN coal tar dyes because 
the synthetic dye industry and explosive industry 
go hand in hand. 


13 


INSENSIBLE 
TO SHOCK 


CHEMICAL 

STABILITY 


IGNITION 

POINT 


THREE 

PROCESSES 


MONO- 

NITRO- 

TOLUOL 


DI-NITRO- 

TOLUOL 


T N T is quite insensitive to shock or, of course, 
it could not be fired from high velocity cannon. 

The authorities claim with great solemnity 
that TNT has great chemical stability, but 
still the authorities also admit that with all coal 
tar explosives the molecules of the compound 
are “in somewhat unstable” condition, to which 
I would add in all humility (being only a layman) 
that the “atoms” must be in a ferment and 
“electrons” must be in a raging fever. We in¬ 
surance men had better discount somewhat the 
assertions about the safety of T N T. 

Every underwriter maintains a powerful inter¬ 
est in “ignition points”. The ignition point of 
T N T is 538° F. although decomposition com¬ 
mences at about 300° F. The textbooks assert 
that it will not explode at the ignition point, but 
there cannot be many degrees difference between 
the ignition and the explosion point. 

The manufacture of T N T is quite simple. It 
can be made by the One, Two or Three Stage 
Process. As the latter is the best and most 
interesting we will study it. 

First the toluol is nitrated as we have nitrated 
benzol and we obtain mono-nitro-toluol. 

After withdrawing the waste acid, the mono- 
nitro-toluol is brought into contact with mixed 
concentrated nitric and sulphuric acid. The 
nitrating pan has to be steam heated to 194° F. 
We now obtain di-nitro-toluol. This material 
at first looks like oil but after cooling it becomes 
a light yellow crystalline solid. 


14 


DISSOLVED 

MIXED 

DIGESTED 

TRI-NITRO- 

TOLUOL 

REFINING 


IF 


MORGAN 

DISASTER 


The di-nitro-toluol is now dissolved with four 
times its weight of “oleum” or fuming sulphuric 
acid and this has to be done with steam heat, and 
the dissolved or sulphonated di-nitro-toluol is 
run into a mixing pan with concentrated (92%) 
nitric acid. 

When mixed thoroughly, the substance is 
placed in a steam heated digester (temperature 
about 248° F.) and after about one and a half 
hours, when no further poisonous gases are given 
off, the waste acids are discharged and the TNT 
is allowed to cool, and is washed with hot water. 
It solidifies at 177° F. into a glistening white, 
crystalline substance. Exposure to the air dis¬ 
colors it to yellow and finally to orange. 

The crude TNT thus obtained can be refined 
or purified by mechanical means (centrifuging) 
or with ethyl alcohol, sulphuric acid, sodium 
sulphite, mixed tetra-chloride of carbon and 
alcohol, acetone, etc. However most of the 
TNT made in this country is not refined. 

Now if our factories used chemically pure 
toluol and chemically pure nitric and sulphuric 
acid, and if the manufacturing processes were 
carried out by perfectly functioning apparatus 
under absolute temperature control, and if the 
employees were highly intelligent and exceedingly 
careful, we would never have had a Morgan dis¬ 
aster. But, commercial toluol contains many 
other things beside toluol, especially the olefines 
which form unstable nitration products, the 
acids are notoriously impure, the apparatus con¬ 
stantly attacked by nitric acid must become 
imperfect, people, especially munition hands, 


15 


VENTURESOME 


HAZARDOUS 

PROCEDURE 


BLACK SMOKE 


JACK 

JOHNSONS 

MIXTURES 

HALOGENATION 

MONOCHLOR- 

BENZOL 


CATALYST 


will become careless for they are of necessity 
recruited from among the venturesome, and 
under present conditions a considerable percent¬ 
age cannot even speak English, and therefore let 
no one be foolish enough to imagine that the 
manufacture of T N T will ever be anything else 
but a most hazardous procedure. 

And now just one more digression from our 
subject. You remember perhaps how in the 
“first” pamphlet we noted that coal tar products 
when burning give off excessive amounts of 
black smoke owing to the excess of carbon, and 
how this excessive amount of smoke interferes with 
the firemen. The same excess of carbon is in 
evidence when “exploding” them. You have 
read about, or perhaps seen, the “Jack Johnsons” 
or “Coal Boxes” explode, with their dense black, 
sooty clouds. The blackest of all are the picric 
acid shells. 

However, a number of the explosives now in 
actual use are more or less complex “mixtures”. 

The “third” process on our list is halogenation. 
This sounds rather formidable until we recall that 
the “halogens” are the chlorine, bromine, iodine 
family, when we again feel thoroughly at home. 

The commonest halogenation process is the 
manufacture of chlorobenzene or monochlorbenzol 
by passing a stream of chlorine through benzol 
in the presence of a “catalyst”. The catalysts 
used in this process are generally ferric chloride 
and iron. 

A catalyst is a compound or simply a plain 
metal which enables the chemical action to take 
place, or which accelerates the action. Some- 


16 


LESSENS 

thing like a lubricant in the mechanical world. 
The chemists even to this day do not quite 
understand the nature of the action involved, 
but catalysts were discovered accidentally and 
are now used quite extensively. The subject of 
catalysts is at present being studied very ex¬ 
haustively and will, no doubt, play quite a role in 
the chemistry of the future. 

Chlorination, or halogenation in general, seems 


INFLAMMABILITY to lessen the inflammability of coal tar deriva- 


CHLORO¬ 

BENZENE 

tives. 

. Strange to say, however, chlorobenzene or 
monochlorbenzol enters quite extensively into 
the manufacture of explosives. 

In a chlorobenzene plant we will generally find 
a still with condensing apparatus delivering the 
benzol at an easily controlled temperature into a 
chlorinating vessel where it encounters a stream 
of chlorine, generally from a cylinder containing 
liquified chlorine. 

The hydrochloric acid gas formed by the re¬ 
moval of one of the hydrogen atoms from the 
benzol ring, passes out near the top and the 
chlorobenzene automatically flows back to the 
still. The benzol gradually becomes richer in 
chlorobenzene, till at last practically all the 
benzol is chlorinated. 

CONTINUOUS 

CHLORINATING 

The chlorination process can, of course, easily 
be made a continuous one, without the danger 
incurred in a continuous “nitrating’’ process. 
Thousands of tons of chlorobenzene are produced 

SULPHUR 

SLACKS 

yearly. It is used mainly in the manufacture of 
sulphur blacks. 

Pure chlorobenzene is a colorless liquid with a 


17 


BENZYL- 

CHLORIDE 

CHLORINE 


REDUCTION 


faint but agreeable odor. The manufacturing 
hazard is pronounced but quite insurable. 

Toluene is also extensively chlorinated, giving 
us benzyl-chloride, also used in the dye industry. 

In view of the ghastly publicity chlorine gas 
has received on the battlefields of Europe, it is 
hardly necessary to draw attention to the fact 
that under no circumstances must the gas be in- 
haled. This takes on added importance when 
it is recalled that chlorine gas is rapidly coming 
into extensive use in our steam laundries, adding 
a new risk to the multitude of risks incurred by 
our firefighters. 

Reduction is the “fourth” of the processes on 
our list. Nitration adds to a coal tar or “aro¬ 
matic” compound a certain amount of oxygen and 
nitrogen. Now the object of “reduction” is to 
remove all or part of the oxygen and to substitute 
hydrogen. 

For example: Benzol is six parts Carbon and 
six parts Hydrogen, expressed for short as: C 6 H 6 . 

Mono-nitration takes away one of the Hydrogen 
atoms and substitutes one part Nitrogen and two 
parts Oxygen expressed as: N0 2 , so that after 
the mono-nitration process is completed we 
obtain C 6 H 5 N0 2 or Mono-nitro-benzol. 

Now the “Reduction” process means the 
taking away of one or more of the Oxygen atoms 
and substituting Hydrogen, which means in the 
case of Mono-nitro-benzol the changing of 
C 6 H 5 N0 2 into C 6 H 5 NH 2 or aniline oil. 

Incidentally, there will be some water (H 2 0) 
left over in this chemical reaction. 


18 


NASCENT 

HYDROGEN 

The reduction process depends generally on 
“nascent” hydrogen which is produced in the 
reduction kettle by the action of cast-iron borings 
on hydrochloric acid. Hydrogen is the lightest 
of all the gases, and, incidentally, the most in¬ 
flammable and explosive. It just hates to be by 
itself, but seeks a chemical combination, and 
when in the “nascent” state, the combination is 
often accomplished by means of an explosion. 

ANILINE OIL 

The most common of all the reduction pro¬ 
cesses is the reduction of nitro-benzene into 
aniline oil. 

You will find the reduction pans to be made of 
cast-iron, and they will hold anywhere from 
1000 to 10,000 lbs. of nitro-benzene. 

The pan is equipped with a powerful stirring 
apparatus. 

Nitro-benzene is placed in the pan, steam is 
turned on, power stirrer is started, hydrochloric 
acid is added, and cast-iron borings (swarf) are 
dropped in slowly, the apparatus being designed 
that no gases can escape while this is being done. 
You can easily imagine that the whirling around 
of the cast-iron borings in the pan causes excessive 
wear, and arrangements for easy replacement of 


WEARING PARTS the wearing parts are quite essential. 


EXPLOSION 

It must be emphasized that the iron has to be 
added very carefully as otherwise an explosion 
may result. 

Aniline oil is from our standpoint quite harm¬ 
less, and it is the starting point for over one-half 
of the synthetic dyes. 


19 


POISONOUS 

FUMES 


NITRO- 

TOLUOL 


TOLUID! N E 


ALKALI 

FUSION 


The fumes given off during the manufacture of 
aniline are poisonous and you will always find a 
well designed aniline oil manufacturing plant 
with very large openings in the walls, in fact the 
less wall, the better. Naturally, if we find the 
building quite open, the explosion hazard is 
considerably reduced. To obtain a first class 
explosion the gases must meet with initial re¬ 
sistance. 

Reducing is also done in some processes with 
pure hydrochloric acid. 

In exactly the same manner as we nitrate 
benzol into nitro-benzol so do we nitrate toluol 
into nitro-toluol, but instead of obtaining ONE 
kind of nitro-toluol we obtain TWO kinds, known 
as ortho-nitro-toluol and para-nitro-toluol, or, 
if you prefer, toluene. 

Similarly, after obtaining nitro-toluol we can 
reduce it, as we reduce nitro-benzol. Reducing 
ortho- and para-nitro-toluol gives us ortho- 
toluidine and para-toluidine, very important 
intermediates. 

There is also a meta-nitrotoluol and a meta- 
toluidine, but they are obtained in a different 
manner. 

The “fifth” process in our somewhat arbi¬ 
trarily arranged list is alkali fusion. Caustic 
soda, chemically known as sodium hydroxide, 
with which we are all familiar, is used in this 
process. Caustic soda and water are placed in 
an iron vessel, equipped with stirrer, and generally 
heated by a bituminous coal fire. After the 
caustic soda is completely liquified, the material 
to be treated is added. 

Sometimes the process involves heavy pressures 


20 


ALKYLATION 


DIMETHYL- 

ANILINE 


AUTOCLAVE 


\ 


when an “autoclave” is used, which piece of 
apparatus we shall discuss in detail later on. 

Aside from the possibility of “heavy pressures” 
the hazard of alkali fusion is mild. 

The “sixth” process, alkylation, has nothing 
whatever to do with alkali. It refers to the 
action of methyl or ethyl alcohol on coal tar 
derivatives. Sometimes formaldehyde is used 
or alkyl sulphates. This process is also named 
esterification, but the name alkylation is better, 
especially in leading our fraternity astray. 

We shall most likely come across a typical case 
of alkylation in a Dimethylaniline plant. Di- 
methylaniline is a colorless liquid used extensively 
in the manufacture of methyl violet, malachite 
green, methylene blue, methyl orange, etc. 

It is also used in the explosive industry. 

Dimethylaniline is made by heating aniline 
oil, acetone free methyl alcohol (wood alcohol) 
and sulphuric acid in a cast-iron autoclave. 

An autoclave is a very substantial, cast-iron 
receptacle, designed and constructed to resist 
very heavy pressures. The autoclave may be 
heated by steam, super-heated steam, gas, 
coke, coal or even fuel oil. 

If the autoclave is “direct fire” heated it should 
be protected against unequal heating or against 
burning through by a double shell with air space, 
or by an oil bath (high boiling point oil), or by 
a sand bath, or by a well constructed firebrick 
arch, or, best of all, by a bath of fusible metal 
(70% lead and 30% tin). Direct fire heated 
autoclaves, without some suitable form of protec- 


21 


DIMETHYL- 

ANILINE 


480 POUNDS 
PRESSURE 


METHYL 

ETHER 


DIRECT 

FIRE 

HEAT 


STEAM 

TEMPERATURES 


tion, are bound sooner or later to cause a serious 
fire or explosion. 

Of course the autoclaves should be provided 
with thermometers (preferably of the recording 
type), pressure gauges and safety valves. Quite 
often the interior of the autoclave has to be pro¬ 
tected against the action of the acids by enamel 
or an acid resisting metal. 

But let us resume the manufacture of dimethyl- 
aniline. After aniline, wood alcohol and a small 
amount of sulphuric acid have been placed in the 
autoclave, it is gradually heated to 446° F. and 
to 455° F. In about four hours the pressure will 
reach 420 or even as high as 480 lbs. per square 
inch. This pressure is maintained for about 
three hours and then falls off gradually. Six 
hours later the fire is extinguished. 

The following day the gases (mainly methyl 
ether) are blown off through a water column, and 
the product is forced by compressed air into a 
steam heated still, is neutralized with caustic soda 
and is distilled off, the pressure in the still often 
rising to 75 lbs. The dimethylaniline is generally 
purified by re-distillation. 

You are no doubt properly impressed in the 
above story by the high pressures used and by the 
fact that direct fire heat must be employed for 
the autoclaves. Steam cannot be used. 

According to our good and useful friend 
“Kent”, steam under 100 lbs. pressure is only 
327.6° F., under 200 lbs. pressure 381.6° F., and 
under 300 lbs. pressure 417.4° F. Of course, 


22 


superheating will help considerably, but still it will 
not furnish the required temperatures. Far be it 
from me, a fire insurance inspector, to advocate 
higher pressures on long lines of steam piping, 
subject to all the ill effects of corrosion through 
acid fumes, the natural contraction and expansion 
through differences in temperatures, the strain 
caused by settling of supports, and the chances 
of mechanical injury. 

AUTOCLAVE In other words, our autoclaves must be fire 

BUILDINGS heated and they must withstand heavy pressures 
created by highly inflammable or explosive gases, 
and therefore we will see to it that the “autoclave 
buildings” are fire-proof and detached. 

AM I DAT! ON The “seventh” process we will discuss in our 

rapid journey through the mysterious land of 
the Coal Tar Intermediates (we are, to be sure, 
using seven-league-boots in hastily skipping over 
the ground) is amidation. It has nothing what¬ 
ever to do with Amida, the Buddha so greatly 
revered by our Japanese allies, but it refers to the 
action of concentrated aqua ammonia on a coal 
tar derivative. A sulphite will greatly help in 
the process. 

/3-NAPHTrlYLAMINE A good and frequently encountered example of 
amidation is the manufacture of /3-Naphthyla- 
mine, which is made from /3-Naphthol (page 38), 
ammonium sulphite and aqua ammonia [20%] 
which are placed in an autoclave and heated to 
302° F. for several hours. The /3-Naphthyla- 
mine thus obtained is pinkish white, but further 
refining gives colorless, odorless crystals. /?- 
Naphthylamine is used in making red azo dyes. 


ACYLATION 


ACETANILIDE 


ACETANILIDE 


Amidation is, of course, a very mild process 
when compared to nitration or to sulphonation, 
still it is worth while to watch the “pressures’" 
employed and to note the method of “heating’" 
the autoclaves. 

Acylation, the “eighth” and last process on our 
list, deals with the action of acetic, formic and 
similar acids on coal tar products. 

* The manufacture of Acetanelide will give us a 
good and very easily understood example of the 
process. 

This time, for a change, the receptacle used is 
an aluminum one, which is set in an iron pan, 
with one or two inch air space between, and this 
double pan is set in a brick furnace, generally 
heated with coal. 

The aniline and the acetic acid are placed in 
the aluminum pan which is heated to 248° F. 
The temperature is gradually raised and towards 
the end of 48 hours the temperature is about 
464° F. The vapors [dilute acetic acid] distill 
over and are cooled and collected. During the 
process, which lasts about three days, more glacial 
acetic acid is generally added. The resulting 
acetanilide is cooled and ground. 

As far as we are concerned, we can class the 
hazard as moderate, that is, in comparison with 
the other hazards of the Coal Tar Industry. 

We find the finished Acetanilide to be white, 
lustrous crystalline scales, the starting point of 
several other Coal Tar Intermediates. 

And here we have arrived at an interesting 
point where the synthetic “Dye” industry and 


24 


ANTIFEBRINE 


the synthetic “Drug” industry overlap, for 
acetanilide is known to the Drug trade (since 
1887) as Antifebrine and it has pronounced 
antipyretic and antirheumatic properties. When 
you take a dose of Bromo-Seltzer, you are swallow¬ 
ing 3! grains of acetanilide. 

In our discussion of the eight principal manu¬ 
facturing processes of the Intermediate Industry, 
we briefly considered the manufacture of nitro- 
benzol, nitro-toluol, nitro-naphthalene, aniline 
oil, ortho- and para-toluidine, chlorobenzene, 
benzylchloride, dimethylaniline, /9-naphthyla- 
mine and acetanilide. But before ending our 
insurancewise discussion of the subject we should 
become acquainted with the manufacture of the 
following important Intermediates to be in a 
position to discuss intelligently the manufacture 
of the Synthetic Dyes in the next pamphlet. 

The additional Intermediates we will now dis¬ 
cuss are: 

Sulphanilic Acid 
/?-Nitroaniline 
Xylidines 
Benzidine 
Salicylic Acid 
a-Naphthylamine 
/9-Naphthol 
Anthraquinone 
Phthalic Anhydride 
Thiocarbanilide 

The study of the manufacture of the above 
Intermediates will, incidentally, bring out several 
points that did not come up in the discussion of 
the previously described manufacturing processes. 


25 


CRIME 


MOLECULAR 

STRUCTURE 


MOLECULE 


H 2 S0 4 


HN0 3 

ARRANGEMENT 

OF 

ATOMS 


When one HAS to commit a crime, for instance: 
to write an expense account, or to discharge a 
very pretty stenographer, one naturally spars for 
time and tries to put off the evil hour. 

Now I am in exactly the same position. I 
have tried conscientiously to explain the “ Inter¬ 
mediates’’ in the language of the 80% Co-Insur¬ 
ance Clause (if that IS language), but we cannot 
proceed much further with the study of the 
Intermediates without committing the very crime 
I have tried so hard to avoid, and that is: We 
will have to clear up the MOLECULAR STRUC¬ 
TURE of the coal tar products, which, by the 
way, is quite unique in the realm of chemistry. 

The chemists imagine, as you doubtless remem¬ 
ber from your happy school days, that all matter is 
composed of small particles, called molecules, and 
that each molecule is made up of a certain number 
of atoms. 

For example one molecule of sulphuric acid 
consists of two atoms Hydrogen (H 2 ), one atom 
Sulphur (S) and four atoms Oxygen (0 4 ), written 
for convenience as: H 2 S0 4 . 

Similarly a molecule of Nitric Acid consists of 
one atom Hydrogen (H), one atom Nitrogen 
(N) and three atoms Oxygen (0 3 ), or, as the 
chemist writes: HN0 3 . 

Now in Coal Tar Chemistry or Organic Chem¬ 
istry the chemist not only knows (or thinks he 
knows) how many atoms and kind of atoms there 
are in a molecule, but he can even tell you how 
they are arranged in the make-up of the molecule. 

Incidentally, the chemists do not know to this 
day how many atoms there are in a molecule of 
Carbon. 


26 


ATOMS 


LE BON 


BENZOL 


BENZOL 

FORMULA 


When I was a boy, our professor of Chemistry 
solemnly assured us that: atoms are the ULTI¬ 
MATE and INDIVISIBLE particles of matter. 
Only 25 years later I find the following definition 
of atoms in the egotistical Le Bon’s “Evolution 
of Matter”: “the atom is a miniature solar 
“system composed of particles revolving round 
“one another without touching and incessantly 
“pursuing their eternal course under the influence 
“of the forces which direct them. Were these 
“forces to cease for a single minute, the world and 
“all its inhabitants would be instantly reduced 
“to an invisible dust.” 

The BASIC coal tar product is benzol or ben¬ 
zene (the same thing). Each molecule of benzol 
is composed of six atoms Carbon and six atoms 
Hydrogen, or C 6 H 6 . 

On the cover of the first pamphlet you will find 
this little diagram 



27 


KEKULE 



TOLUOL 


PHENOL 


which plainly shows six carbon atoms, represented 
by C, arranged in the form of a hexagon, and you 
will notice that each Carbon atom is connected 
with an atom of Hydrogen, represented by H. 

This figure or diagram gives us a clear visual 
representation of how Kekule taught us that the 
atoms of Benzol must be arranged. 

Strange to say Kekule actually dreamed this 
in 1865 while dozing before the fire in the City 
of Ghent, Belgium. You see, after all, pipe- 
dreams have their use, even in the world of science. 

Now up to this day we have not yet found an 
improvement on this admittedly defective repre¬ 
sentation, which for short we write thus | I or 
thus ^ 

Naphthalene simply consists of two benzol 
rings and is written for short as: 

Anthracene consists merely of three benzol 




Toluol or Toluene, first cousin to benzol or 
benzene, is represented by the symbol: CH 3 



Phenol, or Carbolic Acid, is written by the 
chemist as: OH 

y\ 


u 


28 


RADICAL 


GROUP 


RATING 

SCHEDULES 


INDESTRUCTIBLE 

RING 


MONO 

NITRO 

BENZOL 


Dl 

NITRO 

BENZOL 


TRI 

NITRO 

BENZOL 


You see that both Toluol and Phenol are simply 
the ordinary Benzol ring with a little extra attach¬ 
ment called a “radical”. The radical of Toluol 
(CH 3 ) is called the methyl group. The radical 
of Phenol (OH) is called the hydroxyl group. 

Surely, Kekule’s ring system is a great deal 
simpler and easier to understand than our rating 
schedules, and there is a great deal more sense to 
it. 


Now in most of our chemical reactions these 
six Carbon atoms stay “in the ring”, and we can 
act only on the hydrogen. 

For example, in the mono-nitration of benzol 
we only remove the top hydrogen atom and 
substitute the nitro-group N0 2 which is composed 
of one atom of Nitrogen and two atoms of Oxygen. 
In other words C 6 H 6 becomes C 6 H 5 N0 2 written 
N0 2 


for short as 
benzol. 



*\_/ > N0 2 or Mononitro- 


If we go one step further and “DI”-nitrate 
benzol we replace a “second” Hydrogen atom 
with the nitro-group and we obtain: N0 2 
or Di-nitro-benzol. /\ 


N0 2 


And when we complete the nitrating process by 
taking away a third hydrogen atom and replacing 
it with the nitro-group we obtain Tri-nitro-benzol 
written thus: N0 2 


N0 2 


\/no 2 


29 


ORTHO 

META 

PARA 


ALPHA 

BETA 


You see it is quite fascinating and yet exceed¬ 
ingly simple, and you will notice that the six 
carbon atoms may lose some of their hydrogen, 
but they stick together in their good old hexagon, 
an astounding example of brotherly affection in 
the chemical world, an example we poor frail 
humans should try to emulate. 

In reading about coal tar products you fre¬ 
quently run across the prefixes: ortho, meta and 
para, abbreviated as o, m and p. 

These prefixes simply indicate the “position” 
of the substituents, radicals, groups or side- 
chains of the benzol ring, whether they are in the 
first, second or third position. 

These “positions” are also indicated by the 
Greek letters alpha a and beta /?. 

If you will look at the cover of this pamphlet 
you will find a diagram of a-Naphthylamine. 
It is the usual double benzol ring, representing 
Naphthalene, except that the upper right hand 
Hydrogen atom (H) has been replaced by what 
is known as the “amino group” (NH 2 ), which 
changes the naphthalene into a-Naphthylamine, 
or NH 2 described on page 38. 


The Greek letter “a” or alpha indicates that 
the amino group (NH 2 ) is in the “first” position, 
or at the top. 

Should we find the amino group (NH 2 ) one 
step further down we would be dealing with 


30 


1-8-3: 6 


ISOMERS 


SULPHANILIC 

ACID 


“beta” naphthylamine or /?-Naphthylamine, an 
entirely different dye intermediate, represented 
by /x /x NH 2 which we have discussed on 



page 23. 


There is also a method for “numbering” posi¬ 
tions, f. i.: the coal tar chemists speak very glibly 
of l-Amino-8-Naphthol-3 : 6-Disulphonic acid, 
which, for short, is called “H” acid. 

It must now be perfectly plain that the SAME 
atomic constituents of a molecule can give entirely 
different products, simply by a difference in 
position. The various results of the same atomic 
aggregations are known as “isomers”. 

There is, rest assured, a great deal more to this 
ring, position and isomer business, but we will 
let the above suffice, at least until we take up the 
Synthetic Dyes, when we shall be forced to do a 
few more stunts with the benzol rings. For 
instance in manufacturing the Azo dyes we will 
join two benzol rings in the more or less happy 
bonds of matrimony, thus: 



Resuming our study of the Intermediates you 
will recollect that the first Intermediate on our 
list is Sulphanilic acid also known as Para- 
Aminobenzene-sulphonic acid. It is of great 
importance in the manufacture of Azo-dyes. 

It is made by “ sulphonating ” aniline oil which 
gives us aniline-acid-sulphate, and this is after¬ 
wards baked in a fire heated oven when we obtain 
Sulphanilic acid. 


1-8-3: 6 


ISOMERS 


SULPHANILIC 

ACID 


31 


SULPHONATING 

OF 

ANILINE 


ANILINE- 

ACID- 

SULPHATE 


QUITE 

INSURABLE 

/?-NITROANILINE 


“Sulphonating” of aniline oil is done in the 
usual, previously described sulphonating kettle 
which is equipped with powerful stirring appa¬ 
ratus and efficient cooling apparatus. 

Strong sulphuric acid is placed in the kettle, 
stirrer is started, and the aniline oil is “cautious¬ 
ly” added in a thin stream, the process taking from 
three to four hours. 

After all the aniline oil has been added, stirring 
is continued for an additional three or four 
hours. 

The aniline-acid-sulphate thus obtained is 
placed in shallow iron pans in a “cast-iron” fire 
heated oven (temperature 450° F.), and the sul¬ 
phur-dioxide that is liberated is allowed to escape 
through a flue. 

After all the sulphur-dioxide has been driven 
off, the Sulphanilic acid remains in the trays, is 
cooled, ground, is refined by dissolving in dilute- 
caustic soda and is filtered. 

The finished product should consist of colorless 
well formed crystals, but the commercial product 
we insurance men encounter is generally in the 
form of dark grey plates. As stated above it is 
used extensively in the manufacture of Azo-Dyes. 

Since the manufacture of Sulphanilic Acid 
includes the sulphonating of Aniline Oil with its 
inherent fire and explosion hazard, we are fully 
justified in considering the risk involved as: 
“moderately severe”, but in the hands of com¬ 
petent people the risk is quite insurable. 

To manufacture the important dye inter¬ 
mediate /7-Nitroaniline, of which several thousand 
tons are made yearly, we start out with Acetanilide 
(page 24) which, in powdered form, is slowly 
added to sulphuric acid kept in rapid motion in 


32 


37° F. 


/?-NITRO- 

ACETANILIDE 


WRITABLE 


a well cooled “nitrating” pan, care being taken 
that the temperature does not rise above 86° R 

When all the acetanilide is thoroughly dis¬ 
solved, the solution is cooled to 32° F. when we 
start to nitrate in the usual manner with a mix¬ 
ture of nitric and sulphuric acid, but the tempera¬ 
ture must NOT rise above 37° F. or we pay a 
loss. 

In other words the safety of the process, like in 
all nitrating processes, depends on the temperature 
control. 

The nitration product is paranitroacetanilide, 
and we will now have to hydrolize this in order 
to obtain ^-nitroaniline. 

This is done by boiling the paranitroacetanilide 
in caustic soda solution, which, of course, is non- 
hazardous from our standpoint/ although, for 
the benefit of our brethren in the Employers" 
Liability business, it should be mentioned that 
the fumes given off are highly poisonous and 
should be carefully led out of the building. 

After the hydrolysis is completed, the solution 
is allowed to settle and the /?-Nitroaniline is 
filtered out and is ground thoroughly, p- Nitro- 
aniline consists of yellow prisms and is used to a 
large extent for a brilliant red dye (paranitraniline 
red) and is used in several other important dyes. 

Since its manufacture includes a decided 
“nitrating” hazard, we must naturally class its 
manufacture as quite hazardous, but with the 
proper type of plant, run by the proper people. 


33 


XYLOL 


XYLOL 

ISOMERS 


META¬ 

XYLOL 

SUBMARINES 

70% TO 85% 

XYLIDINES 


there is no reason why we should not stake our 
stockholders’ good money on it. 

Perhaps you remember that in the description 
of the distillation of Crude Benzol we mentioned 
on page 11 of the “first” pamphlet that we 
obtained, among other ingredients, the oil 
Xylol. 

Then on page 12 of the same pamphlet you 
will find it stated that Xylol is a combination of 
three products. Now, that we are acquainted 
with the molecular arrangement of the aromatic 
compounds, we can state that these three products 
are the isomers: ortho-xylol, meta-xylol and 
para-xylol, written thus: 


CH 3 ch 3 ch 3 



ch 3 


Ortho-Xylol Meta-Xylol Para-Xylol 

By the way, Uncle Sam now nitrates Meta- 
Xylol for filling depth-bombs, thus linking up 
the Coal Tar Industry with the despised Sub¬ 
marines. 

Meta-xylol is the principal constituent of 
ordinary xylol, in fact 70% to 85%. 

When we mono-nitrate the mixture of the 
three xylols we obtain crude mono-nitro-xylol. 
And when we reduce this we obtain the crude 
xylidines, a harmless oil used extensively in Azo 
dye making. 


34 


BENZIDINE 


HYDRAZO- 

BENZENE 


The crude Xylidines can be separated into two 
Ortho-Xylidines, three Meta-Xylidines and one 
Para-Xylidine, in all six isomers, but to describe 
all those processes would take too much of 
your time and would run my printer’s bill up 
too high. 


Benzidine or Di-para-amino-di-phenyl is one of 
the most important intermediates used in the 
manufacture of the Disazodyes, the only dyes, as 
we will see in the next pamphlet, involving a pro¬ 
nounced “explosion” hazard. 

Benzidine is made in various ways, but the 
following process is the most interesting to us: 

Nitrobenzene is placed in a closed, double 
walled or jacketed, cast-iron pan with power 
stirrer, alcohol is added, the mixture is heated to 
the boiling point of the alcohol, after which zinc 
dust is added (iron is used in some plants). 
Slowly a mixture of alcohol and sodium hydroxide 
(caustic soda) is added, the contents of the kettle 
being kept boiling gently by steam in the jacket 
of the kettle. The pan is fitted with a reflux 
condenser, so that all the gases are cooled and 
returned to the pan. When the “reduction” is 
complete, water is added, and the alcohol is 
distilled from the mixture by steam heat. 

The residuum in the pan is screened, to remove 
the zinc dust, zinc oxide, etc., and the hydrazo- 
benzene is filtered off. 

The hydrazo-benzene is treated with an excess 
of hydrochloric acid, filtered, and the filtrate is 
precipitated with sulphuric acid. The sulphate is 
boiled with caustic soda. The benzidine is 
filtered off and can be purified by distilling in a 
vacuum. 


35 


ZINC 

DUST 


SALICYLIC ACID 


ASPIRIN 


DRY 

DISTILLING OR 
SUBLIMING 


Pure benzidine forms large colorless silky plates. 

Its manufacture always involves the pre¬ 
viously discussed “reduction” hazard (nascent 
hydrogen), and it may involve the use of zinc 
dust and alcohol. The benzidine manufacturing 
hazard is therefore rather severe but fully writable. 


To obtain salicylic acid, sodium phenoxide 
[obtained from phenol and caustic soda] is heated 
in an autoclave to about 266° F. and carbon 
dioxide under heavy pressure is fed into the auto¬ 
clave. After the chemical reaction is completed 
the contents of the autoclave is dissolved in water 
and the salicylic acid is precipitated by adding 
sulphuric acid. The salicylic acid is filtered out 
and recrystallized. The acid can be further 
purified by dry distillation or sublimation with 
superheated steam, when the product will be 
snow white. 

It is used extensively in the dye industry 
(Alizarin Dyes), it is also used as a food and beer 
preservative, and most of us have consumed con¬ 
siderable quantities in the form of acetyl-salicylic 
acid known popularly as “aspirin”. 


When we have a solid, such as salicylic acid, 
or naphthalene, anthracene, etc., and we refine or 
sublime it by dry distillation, we incur an explo¬ 
sion hazard that is but imperfectly realized by the 
insurance fraternity. 


I distinctly recall my first experience with “ dry ” 
distillation or subliming. Several negroes were 
engaged in refining crude Japanese camphor in 


36 


CAMPHOR 

EXPLOSION 

fire heated stills which discharged into brick sub¬ 
liming houses. I was very much interested to 
learn a few weeks later that the sons of Ham, 
stills, camphor and all had been blown into the 
Delaware River. 

NAPHTHALENE 

EXPLOSION 

My second experience was in a naphthalene 
subliming plant. The subliming house was of 
wood. The process being finished, the doors were 
opened and an honest if not handsome Polack 
started to shovel the beautiful white stuff into a 
cart when suddenly Polack, shovel, cart and all 
were projected into that world of which we hear 
so much and know so little. 

STILL 

BURNS 

THROUGH 

The camphor explosion was due to the still 
“burning through”, which is quite a habit with 
direct fire heated stills. 

EXPLOSIVE 

MIXTURE 

The naphthalene explosion was due to the 
Polack striking a spark with his shovel, but in 
both cases the effect depended on the explosive 
mixture of camphor and naphthalene gases and air. 

In other words, whenever we refine or sublime 
by “dry” distillation, unless it is done in a 
vacuum, we project into an air filled room a large 
amount of hot and inflammable gases, and as a 
rule, we have an explosive mixture. All that is 
needed is a spark or a flame. 


I trust you will pardon this long digression, 
but so much surprise has been expressed by a few 
recent explosions of this type that it seemed worth 
while to explain this point at length. 


37 


a-NAPHTHYLA- 

MINE 


/3-NAPHTHOL 


In order to obtain a-Naphthylamine [see cover 
and notes on page 30] we first “nitrate” naphtha¬ 
lene at not exceeding 140° F. and obtain nitro- 
naphthalene. We now place in a “reduction” 
pan the proper quantity of swarf (iron) and 
hydrochloric acid and some water. This mix¬ 
ture is warmed and the nitro-naphthalene is 
slowly added, the temperature being main¬ 
tained during the reduction process at 122° F. 
Of course all the time the stirrer is in operation. 
Finally slaked lime is added, and the product is 
run out into flat iron trays which are placed in a 
fire heated retort. Superheated steam is blown 
into the retort to facilitate the removal of the 
naphthylamine, which distills off as a black oil 
and crystallizes. The crude naphthylamine is 
redistilled with direct fire heat and becomes almost 
water white. It crystallizes into flat white 
needles or plates. It has, strange to say, an 
unpleasant (fecal) odor. It is a very important 
intermediate in the manufacturing of dyes, 
especially the Azo dyes. 

The fire and explosion hazards, while not ex¬ 
cessive, are pronounced, the hazard being accentu¬ 
ated by the liability of apparatus becoming choked 
through crystallization, which needs very careful 
watching. 

Still naphthylamine plants have been operating 
for years without trouble and are generally quite 
acceptable risks. 


To make this important intermediate, which 
stands in the same relation to naphthalene as 
phenol stands to benzol, we commence by sul- 
phonating naphthalene at 338° F., when we obtain 
Naphthalene-/3-Sulphonic Acid. 


38 


ANTHRAQUINONE 


PHTHALIC 

ANHYDRIDE 

INDIGO 

INTERMEDIATE 


This acid is dissolved in water, salted out y 
filtered and dried when we obtain Sodium Naph- 
thalene-/3-Sulphonate. This, in turn, is fused 
with a caustic soda solution, and is then mixed 
with hydrochloric acid. 

The /9-Naphthol, thus obtained, is filtered out 
and is purified by vacuum distillation when it 
forms white crystalline plates or leaflets. It is 
used, especially its derivatives, in the manu¬ 
facture of Azo dyes. 

Even if the manufacturing hazard includes the 
sulphonating of naphthalene, it can be classed y 
under proper management, as quite insurable. 


Anthraquinone is made by oxidizing anthracene 
with chromic acid in lead lined tanks. The 
oxidation takes about fourteen hours and has to 
be carried out carefully. When the oxidation is. 
completed, the material is filtered, and the anthra¬ 
quinone is purified by sublimation with super¬ 
heated steam. In the subliming process we must 
again be careful to avoid closing up of the outlet 
by crystallization. 

The chromic acid used in the process is obtained 
by mixing sodium dichromate with sulphuric 
acid, the chromium being recovered later at the 
filter presses. Commercial anthraquinone is yel¬ 
low, but pure anthraquinone is almost white. 

The manufacturing hazard may be classed as 
moderately hazardous. 

Phthalic anhydride is not only an important 
intermediate in the making of red, violet and 
yellow dyes, but its manufacture is the first step in 
the synthesis of Indigo, the crowning glory of 
systematic and patient chemical research. 


39 


OXIDATION 

PAN 


MERCURY 


SUBLIMES 


To make phthalic anhydride we first dissolve 
naphthalene in fuming sulphuric acid (oleum) 
and we do this in an iron pan equipped with the 
usual stirring apparatus. 

After about three hours’ vigorous stirring, the 
dissolved naphthalene is discharged into a storage 
tank. 


In the next step in this process, the dissolved 
naphthalene is “oxidized” in a brick set, flat, 
direct fire heated (generally “gas” heated) closed 
pan with stirrer, pressure gauge, and a peculiarly 
constructed condenser. 


Before the dissolved naphthalene is run into 
the “oxidation” pan, we have to provide a 
“catalyzer” which, in this case is mercury or, 
rather, its salts. The mercury is placed in the 
pan with sulphuric acid and the acid is carefully 
distilled off, leaving the mercuric salts in the pan. 

After the catalyzer is thoroughly distributed, 
the dissolved naphthalene is introduced into the 
oxidation pan, a few gallons at one time, and is 
rapidly distilled over into the condenser at a 
temperature of about 572° F. Or, rather, the 
sulphuric acid “distills” over and the phthalic 
anhydride “sublimes” over. 


The sulphur dioxide formed is taken care of by 
a vacuum system and is, of course, returned to 
the sulphuric acid plant. 


40 


RESUBLIMATED 


QUITE 

INSURABLE 


ACCIDENT 


THIOCARBANILIDE 


REFLUX 

CONDENSER 


On the bottom of the pan, charred matter ac¬ 
cumulates, which, eventually, puts the catalyzer 
hors de combat and has to be chipped away after 
two or three days running. 

The phthalic anhydride and the sulphuric acid 
collect together in the condenser and have to be 
separated in a rotary extractor or “whizzer”. 

The phthalic anhydride is generally sublimated 
a second time by direct fire heat (coke fire). 
Pure phthalic anhydride sublimes in beautiful 
long colorless needles. 

From our standpoint the entire process is, of 
course, quite hazardous, but under good technical 
supervision, the process is quite insurable. 

As mentioned, the manufacture of phthalic 
anhydride is the first step in the manufacture of 
Synthetic Indigo, and, strange to say, the com¬ 
mercial success of Synthetic Indigo was held up 
for quite a while on account of the great cost of 
this first process, when, fortunately, through the 
accidental breaking of a mercury thermometer, 
the catalyst was supplied that enabled the 
“oxidation” to take place. Thus does the course 
of true science, like the course of profitable under¬ 
writing, depend to a great extent on ACCI¬ 
DENTS. 

Thiocarbanilide or Di-phenyl-thiourea, use 
whichever name you may fancy best, is made by 
mixing aniline oil, carbon-bisulphide and alcohol 
in a closed steam heated pan equipped with 
“reflux” condenser, which means a condenser 
that liquifies the gases given off and returns the 
liquid to the original receptacle. 


41 


SULPHURETED 

HYDROGEN 


CARBON-^ 
BISULPHIDE 


TRAVELS 

FAST 


IGNITES AT 

293° F. 


This gentle boiling is kept up for an entire day 
and during this time sulphureted hydrogen is 
evolved, and the pleasant part about sulphureted 
hydrogen is its edifying odor, which very closely 
resembles that of antique eggs. Naturally a 
thiocarbanilide factory is immensely popular with 
the neighbors. 


The solid mass of crystals remaining in the pan 
is washed and dried. 

Pure thiocarbanilide forms colorless rhombic 
plates and is used in the manufacture of Indigo 
by the Sandmeyer method. 


The only reason I included Thiocarbanilide in 
the short list of Intermediates described in this 
pamphlet is the use of Carbonbisulphide in its 
manufacture. 


Carbonbisulphide is far more dangerous than 
gasoline. It evaporates much more readily than 
gasoline and it has, mixed with air, the widest 
known range of explosibility. 


Like gasoline, the vapors of carbonbisulphide 
are heavier than air and travel along the ground 
and are fond of cellars and other depressions. 
The only difference between gasoline vapors and 
carbonbisulphide vapors is that carbonbisulphide 
vapors travel much faster and are much harder 
to dispel. 

Carbonbisulphide boils at 117° F. and ignites 
when heated to 293° F. In other words a steam 


42 


FAMILY 

TREE 


pipe is sufficient to cause a fire or explosion. 
With no other liquid or gas in common use do we 
encounter so low a boiling point and ignition 
point. The boiling point of Benzol is 178° F. 


The Thiocarbanilide Building should be very 
well isolated from the balance of the plant, 
irrespective of its arrangement, construction and 
protection, and it should pay, regardless of the 
eloquence of the broker, at the very least 5% 
per annum. 


And now, that we have finished getting ac¬ 
quainted with the Intermediates, let us take 
another look at the Coal Tar Family Tree. 

If you will compare it with the tree in the “first” 
pamphlet you will find that we have sprouted a 
new series of branches, and they in turn are now 
ready to supply the twigs for the ultimate result, 
the “dyes”. 


43 


PARANITROANILINE 






COAL 



"coal-tar-intermediate- plants: 

Wm.Vlachos. 

Fire Insurance Inspector. 
Philadelphia, Pa. 



TAR 







SUGGESTIONS 

The question naturally arises: What can we 
fire insurance men suggest to lessen, or perhaps 
eliminate, the hazards involved in the manufacture 
of the Intermediates. 

Aside from suggesting fire-proof construction, 
adequate ventilation, thorough isolation of hazard¬ 
ous processes, and abundant fire extinguishing 
apparatus and regularly trained fire brigades, I 
am, after a more or less extensive study of the 
problem, very much tempted to propose that 
we suggest to the assured what Colonel George L. 
Shepley so cleverly describes in his: “Insurance 
Practices in Foreign Countries”. He found that 
in certain parts of Europe the property owners, 
as a fire preventive, affix a fac-simile of their 
patron saint to the facade of the building. 

PATRON 

SAINT 

I have not the slightest idea who the patron 
saint of the Coal Tar Industry might be, but, of 
course, OUR patron saint is the versatile Benjamin 
Franklin, the most famous of Philadelphians, 
and the first American to write and publish a 
paper: “on the different accidents and careleffneffes 
by which houfes were Jet on fyre, with cautions 
againft them, and means propofed of avoiding 
them” 

DENOUEMENT 

But, leaving the saints aside, we now come to 
the happy part of the story, the denouement. 
After all we have seen and discussed: What is the 
verdict? Can we write the Coal Tar Inter¬ 
mediate Plants? 

ADEQUATE 

RATE 

We can write good sized lines on Coal Tar 
Intermediate Plants provided the rate is ADE¬ 
QUATE. Furthermore we will, of course, prefer 


46 



plants that are scattered over considerable area, 
plants that consist of distinct buildings for each 
process, with wide, open yard spaces between. 
In other words, plants “built for the purpose”, 
and not a made-over-foundry or an altered- 
wagonworks. 

FIRE-PROOF 

The sulphonating, nitrating, reducing and 
autoclave buildings should be fire-proof. 

PROTECTION 

The protective or fire extinguishing apparatus 
ought to be planned on thoroughly efficient lines. 

AUTOMATIC 

SPRINKLERS 

Automatic sprinklers, while desirable, should 
not lead us to materially increase our NET reten¬ 
tion, the hazard generally being too severe for 
sprinkler control. Explosions are perhaps more 
likely to occur than fires, and the first result of 
an explosion is a disruption and bleeding of the 
sprinkler system. The extensive use in these 
plants of the strongest known acids naturally 
shortens the life of a sprinkler system, and in most 
of the plants a “DRY” system is unavoidable. 

HYDRANT & 

HOSE 

Our reliance will have to be placed on first class 
hydrant and hose systems supplied by large public 
w r ater works or by large, well located, private 
pumps. Fire brigades should be organized among 
the day and the night forces of the plant and they 
should be drilled regularly. 

MORAL 

HAZARD 

The financial standing of the concern should be 
unquestionable. This business requires large 
outlays of “real” money, and is no business for a 
fly-by-night stock brokerage scheme. 


47 


TECHNICAL 

SUPERVISION 


GUESSWORK 

HOUSE¬ 

KEEPING 


EXPOSURES 


WRITE 

FREELY 


As the entire success of the plant depends on 
the capabilities of the technical staff, we should 
make it a point to find out whether the chemists 
in charge have been properly educated technically 
and also if they have sufficient “practical” 
experience. A man may teach chemistry at one 
of our best colleges for twenty years and yet be an 
utter failure at managing a chemical works. 

A chemist not very far from my office was going 
to make his fortune by manufacturing “sulphur 
black”, a popular dye for hosiery. He invested 
his own and other people’s money quite freely 
because he could make sulphur black in his 
laboratory. But, when he commenced to operate 
on a manufacturing scale, he found that he could 
not even di-nitrate naphthalene, the very first 
step in the process, and of course lost all. 

Chemists in this business must not only know 
things in a theoretical way, but they must be 
thoroughly practical. 

It goes without saying, that guesswork in this 
business leads inevitably to fires and explosions. 

Even in coal tar plants, housekeeping, I mean 
good housekeeping, is by far the best fire preven¬ 
tive yet invented by the mind of man. Insist on 
it here and everywhere. 

As a large proportion of the best risks bum 
through exposures, we shall, of course, give the 
exposures the proper consideration. 

Personally, I feel no hesitancy whatever in 
recommending that we write the Intermediate 
plants quite freely if the ownership, technical 
management, physical arrangement, housekeeping 
and protection are acceptable and the rate is 
adequate. 


48 


COMPETITIVE 

RATE 


U. & 0. 


VITAL 

POINT 


EXPLOSION 

INSURANCE 


The question of rate is a very complex one be¬ 
cause the plants vary so widely in all the essentials, 
but let no one persuade you to write these plants 
at “competitive” rates, for the hazards are severe 
and call for ample compensation. 


Use & Occupancy Insurance has not of late 
endeared itself to our fire-insurance-hearts, but 
strange to say, as far as the Intermediate plants 
are concerned, U. & 0. appears often rather 
attractive for the simple reason that as a rule 
there are several distinct processes, practically 
independent from one another. 

In properly designed plants a “complete” 
shut-down ought to be almost impossible, unless 
a vital point like the steam boilers or the refriger¬ 
ating machinery is put hors de combat. 


Explosion lines are acceptable provided we are 
covering the type of plant that we would write a 
good sized fire line on. If the plant does not 
measure up to our fire underwriting requirements, 
it is axiomatic that we cannot consider it for an 
explosion line. 

Under any consideration it is hardly within our 
province to issue explosion policies on “di” and 
especially on “tri” nitrating plants. 

Sulphonation and reduction plants should be 
carefully investigated and are generally writable 
for explosion insurance. Before writing “auto¬ 
clave” buildings we should inquire into the 
“pressures” involved, as in some cases they may 
be prohibitive. 

Generally speaking, explosion insurance is 
writable at a rate. 


49 


May the information contained in this pamph¬ 
let aid in a broader understanding and a freer 
underwriting of this class of risks. 

September 26th, 1918. 



50 




A FEW SHORT=CUTS 

ALPHABETICALLY ARRANGED 

(See also short-cuts in “first” pamphlet) 

ACETANILIDE MANUFACTURING —moderate hazard—quite insurable. Page 
24. 

ACETYLSALICYLIC ACID. Page 36. 

ACYLATION —moderate hazard. Page 24. 

ALKALI FUSION —generally a mild manufacturing hazard. Page 20. 

ALKYLATION —serious manufacturing hazard. Involves the action of alcohol 
on coal tar derivatives. High pressure autoclaves. Pages 21 & 22. 

ALPHA (a). Page 30. 

AMIDATION —action of aqua ammonia on coal tar derivatives. Mild manufac¬ 
turing hazard. Pages 23 & 24. 

/>-AMINOBENZENESULPHONIC ACID. Page 31. 

ANILINE-ACID-SULPHATE MANUFACTURING is a rather severely hazardous 
process but insurable under good conditions. Pages 31 & 32. 

ANILINE HYDROCHLORIDE MANUFACTURING— very mild hazard. Write 
freely. 

ANILINE OIL —non-hazardous from fire insurance standpoint. Poisonous. 

ANILINE OIL MANUFACTURING involves a rather serious but quite insurable 
hazard. Avoid makeshift plants. Inspect promptly. Page 19. 

ANILINE SALT is Aniline Hydrochloride, a non-hazardous salt. 

ANTHRACENE MANUFACTURING involves a decided, but under good con¬ 
ditions quite insurable hazard. 

ANTHRAQUINONE MANUFACTURING is moderately hazardous. Quite 
insurable. Page 39. 

ANTIFEBRINE —same as Acetanilide. Page 25. 

AROMATIC COMPOUND refers to a Coal Tar Compound. 

ASPIRIN is acetyl-salicylic acid. Page 36. 

AUTOCLAVES are cast-iron receptacles used for treating coal tar products under 
heavy pressures. The autoclaves are generally direct fire heated. Pages 21, 
22 & 23. 

AUTOCLAVE BUILDINGS should be fireproof, and should be isolated from 
balance of plant. 

BENZALDEHYDE MANUFACTURING is moderately hazardous. Quite insurable. 

BENZENE, correct chemical name for benzol. 

BENZIDINE MANUFACTURING involves a rather severe but fully writable 
hazard. Page 35. 

BENZOL is about as hazardous as gasoline. 

51 


BENZOL DISTILLERIES are quite hazardous but are usually acceptable risks. 
Steam boilers must be absolutely cut off. 

BENZOL RING. Pages 27, 28, 29, 30 & 31. 

BENZYL-CHLORIDE is chlorinated toluene. The manufacturing hazard is 
serious but generally insurable. Page 18. 

BETA (ft). Page 30. 

BRONNER ACID [2-Naphthylamine-6-Sulphonic Acid]. Manufacturing hazard is 
moderately serious. Insurable. 

CARBONBISULPHIDE (Page 42 &43). Of all the liquids used in manufacturing 
processes carbonbisulphide is the most volatile, the most inflammable and the 
most likely to cause explosions. Write only in steel drums. 

CARBONBISULPHIDE FACTORIES, decline absolutely. 

CATALYST is a metal or a compound which, through its presence, enables a 
chemical action to take place, or which accelerates the action. The catalyst 
remains unchanged. Pages 16 & 17. 

CHLORINATION is pronouncedly hazardous. Generally quite insurable. Pages 
16, 17 & 18. 

CHLORINE is a highly poisonous gas used in the coal tar industry for chlorinating. 
Pages 16, 17 & 18. 

CHLOROBENZENE MANUFACTURING involves a decided risk, but well 
equipped plants are quite writable. Page 17. 

CRUDES: Benzol, Toluol, Xylol, Solvent Naphtha, Naphthalene, Phenol, Cresol, 
Anthracene, Pyridene, Quinoline, Acridine, etc. 

DIMETHYLANILINE MANUFACTURING involves the use of high pressure, 
direct fire heated autoclaves. Generally quite writable. Inspect promptly. 
Pages 21 & 22. 

DINITROBENZENE MANUFACTURING involves a serious fire and explosion 
hazard. Inspect before committing Company. 

DINITROTQLUENE MANUFACTURING is a very hazardous process. Inspect 
before accepting liability. Pages 12 & 14. 

DIPARAAMINODIPHENYL. Page 35. 

DIPHENYLTHIQUREA (Pages 41 & 42). Very hazardous manufacturing process 
including the use of steam heated carbon-bisulphide. Inspect before writing 
policy. 

DRY DISTILLING or subliming is done extensively in the Coal Tar Industry and 
involves a moderate explosion hazard. Pages 36 & 37. 

ESTERIFICATION is a serious manufacturing hazard. Page 21. 

EXPLOSION of solid coal tar products generally involves the instantaneous con¬ 
version of the solid matter into the gaseous state, resulting in an enormous 
increase of the original volume and exceedingly high pressure and temperature. 

“F” ACID [2-Naphthylamine-7-Sulplionic Acid]. The manufacturing hazard 
is moderately severe. 

FLAMELESS EXPLOSIVES. Page 12. 

52 


\ 


“G” ACID [2-Naphthol-6 : 8-Disulphonic AcidJ. Manufacturing hazard is severe; 
Inspect promptly. 

“H” ACID [l-Amino-8-Naphthol-3 :6-Disulphonic AcidJ. The manufacturing 
hazard is severe. Inspect before committing Company. 

HALOGENATION (Pages 16 & 17). Treating coal tar derivatives with chlorine, 
bromine or iodine. Pronounced hazard, but quite insurable. 

HYDRAZOBENZENE (Page 35). Rather severe manufacturing hazard, but 
fully writable. 

HYDROGEN is the lightest, most inflammable and most explosive of the gases in 
common use. Particularly hazardous in the “nascent” state. Never insure a 
plant using hydrogen obtained by the electrolysis of water for you will surely 
pay a loss. 

INTERMEDIATES: An indefinite term applied to the Coal Tar Compounds 
between the Crudes and the Dyes. 

ISOMERS (Pages 31 &34) are coal tar products of the same atomic constituency 
but with the radicals in different positions. 

“K” ACID [l-Amino-8-Naphthol-4 : 6-Disulphonic Acid]. Severe manufacturing 
hazard. Inspect before accepting liability. 

KEKULE’S RING. Pages 27 & 28. 

“L” ACID [l-Naphthol-5-Sulphonic Acid]. The complete manufacturing process 
involves serious hazards. Inspect promptly. 

META (m). Pages 30 & 34. 

METAXYLOL, a light coal tar oil, a trifle less hazardous than benzol. Page 34. 

METHYL ALCOHOL— wood alcohol. 

MIXED ACID —used in nitrating is composed of nitric and sulphuric acid. Prac¬ 
tically as hazardous as nitric acid. 

MOLECULAR STRUCTURE of the Coal Tar Products is explained on pages 


26, 27, 28, 29, 30 & 31. 


MONOCHLORBENZOL, see chlorobenzene. Page 17. 

MYRBANE— refined Nitro-Benzol. Harmless oil. Manufacturing processes 
hazardous but generally quite insurable. 


[ Mono! 
Di I 


SULPHONICACIDS involve pronounced manufactur¬ 


ing hazards, insurable only under good conditions. Inspect promptly. 


[ Mono! 

Di I SULPHONIC ACIDS. 


The manufacturing processes 


involve severe hazards. Upon inspection plants may be found quite insurable. 
/3-NAPHTHOL (Pages 38 & 39). Pronounced manufacturing hazard but under 


proper management quite insurable. 

«-NAPHTHYLAMINE. Page 38. The manufacturing hazard is pronounced. 

Under good management quite writable. Inspect. 

/9-NAPHTHYLAMINE. Page 23. Moderate manufacturing hazard. 

NASCENT in chemistry means that the element has just been released from a 
chemical combination. Generally a “nascent” element displays unusual 
chemical activity. Nascent hydrogen often causes explosions. Page 19. 


53 


NITRATION is the action of nitric acid on coal tar products. Always a serious 
and sometimes an uninsurable hazard. Pages 9, 10, 11, 12, 13, 14, 15 & 16. 
Nitrating plants should be inspected before incurring liability. 

NITRIC ACID is the most hazardous of the commercial acids. Carboys should 
not be packed with straw or excelsior, but with asbestos or mineral wool. Store 
nitric acid carboys in the shade, away from all inflammable material. 

/>-NITROACETANILIDE MANUFACTURING involves a decided “nitration” 
hazard. Write only the first class plants. Pages 32 & 33. 

^>NITROANILINE MANUFACTURING is quite hazardous. Insurable under 
good conditions. Inspect promptly. Pages 32 & 33. 

OLEUM —fuming sulphuric acid. Sulphuric acid and sulphur trioxide. Store 
in shade. Keep away from all inflammable matter. Almost as hazardous as 
nitric acid. 

ORTHO (o). Pages 30 & 34. 

PARA (/>). Pages 30 & 34. 

PHTHALIC ANHYDRIDE MANUFACTURING is quite hazardous but under 
good conditions the process is fully insurable. Pages 39, 40 & 41. 

PICRATES are the salts of picric acid. Very unstable and sensitive to shock. 
Exceedingly hazardous. Page 12 & 13. 

PICRIC ACID is Trinitrophenol the most powerful of the Coal Tar Explosives. 
Pages 12 & 13. 

RADICAL. Page 29. 

REDUCTION means the replacing of part or all of the oxygen in a compound with 
hydrogen. The hazard involved is severe. Pages 18, 19 & 20. 

RESORCINOL. The manufacturing processes include “di” sulphonating of 
benzol and extraction with alcohol or ether. If under first class management, 
the risk is insurable. Avoid makeshift plants. Inspect promptly. 

SAFETY EXPLOSIVES. Page 12. 

SAFETY VALVES. Page 10. 

SALICYLIC ACID (Page 36). Hazardous manufacturing process. Insurable 
under careful management and with properly designed apparatus. Inspect 
promptly. 

SUBLIMING: “Dry” distillation. Used extensively in the Coal Tar Industry 
for “refining”. An explosion is always possible, yet seldom occurs except 
through negligence. See pages 36 & 37. 

SULPHANILIC ACID MANUFACTURING is a moderately severe hazard. In¬ 
surable. Pages 31 & 32. 

SULPHONATION refers to the action of sulphuric acid on a coal tar compound. 
Generally a quite hazardous process. Page 8. List the risk for “prompt” 
inspection. 

SYNTHETIC in chemistry means that a compound has been “built up” from its 
elements. For example: Phenol is found as such in Coal Tar but it is also built 
up synthetically from benzol. Indigo is a natural product but it is also built 
up synthetically from naphthalene. 


54 


THIOCARBANILIDE (Pages 41,42 & 43). Very hazardous manufacturing process 
involving the use of carbonbisulphide. Cancel first. Inspect afterwards. 

TOLUIDINE MANUFACTURING involves serious but as a rule quite insurable 
hazards. Page 20. 

TN B means Trinitrobenzol. 

TNT means Trinitrotoluol. 

TN P is an abbreviation for Trinitrophenol or Picric Acid. 

TRI-NITRO-BENZOL, powerful explosive. Pages 12 & 29. 

TRI-NITRO-PHENOL, the most powerful of the coal tar explosives. Pages 
12 & 13. 

TRI-NITRO-TOLUOL, powerful coal tar explosive. Very widely used by the 
Army. Pages 12, 13, 14, 15 & 16. 

WIRE-GLASS is easier shattered by an explosion than ordinary glass. Page 11. 

XYLIDINES (Pages 34 & 35). The manufacturing processes include mono-nitrat¬ 
ing and reducing. Quite hazardous but usually writable. Inspect. 

XYLOL ISOMERS. Page 34. 

ZINC DUST can ignite spontaneously. Never try to extinguish a zinc dust fire 
with water for a serious explosion may result. 


NOTE: 

Early in 1919 I expect to print the third and concluding pamphlet describing 
the manufacture of the “Coal Tar Dyes”. 

W. V. 

October 6th, 1918. 


55 



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PRESS OF 

REVIEW PUBLISHING & PRINTING CO. 

N. W. COR. FOURTH AND LOCUST STREETS 
PHILADELPHIA, PA. 


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